Question

The isomer of C6H14, which will give maximun number of monochloroderivative is
(1) 2,3 dimethylbutane (2) 2-methylpentane
(3) 3-methylpentane (4) Hexane.

Plz explain

Answer 1

For hexane, there is symmetry of the
structure at the 3-4 bond. So chlorine can
attach to the first, second and third carbon.
So we will get three monochlorine
derivatives.
For 2-Methylpentane , chlorine can attach
to any of the five carbons(to the methyl
group too) to give different structures.
Thus, we will get five monochlorine
derivatives.
For 3-Methylpentane, there is symmetry
around the third carbon. So chlorine can
attach to the first, second, third carbon and
methyl group. So we will get four
structures.
For 2,3-Dimethylbutane, there is symmetry
around the 2-3 bond. So chlorine can
attach to first and second carbon to give
two different structures.
Thus, 2,3-Dimethylbutane will have the
minimum number of monochlorine
derivatives.